Bandwidth and Q Factor Calculator for RF Resonators and Filters

Interactive Bandwidth/Q Calculator

Bandwidth ↔ Q Factor Converter

Input Type

Center Frequency (MHz)

Q Factor (for Q→BW mode)

Bandwidth BW (MHz) (for BW→Q mode)

Center Frequency f₀	—
3 dB Bandwidth BW	—
Loaded Q Factor	—
Fractional BW (FBW)	—
Lower −3 dB freq f₁	—
Upper −3 dB freq f₂	—

Q Factor / Bandwidth Reference Table

Filter Type / Application	f₀ (MHz)	BW (MHz)	Q_L
GPS L1 bandpass filter	1575	20	78.8
LTE Band 3 RX SAW filter	1843	75	24.6
5G NR n78 BAW filter	3550	500	7.1
WiFi 2.4 GHz filter	2450	100	24.5
WiFi 5 GHz filter	5500	500	11
Crystal oscillator (10 MHz)	10	0.005	2000

Formulas

  Q_L = f₀ / BW₋₃dB
  BW = f₀ / Q_L
  FBW = BW / f₀ (fractional bandwidth)
  f₁ = f₀ − BW/2  (approximate for narrow-band)
  f₂ = f₀ + BW/2

  Matching network bandwidth: BW ≈ f₀ / Q_match
  Q_match for L-network: Q_min = √(R_high/R_low − 1)

RF View BW Marker: RF View's BW Marker automatically computes f₀, 3 dB bandwidth, and Q_L from any S21 trace. For matching networks: same formula applied to S11 −10 dB bandwidth. Free on Android.

Bandwidth and Q Factor Calculator

Interactive Bandwidth/Q Calculator

Bandwidth ↔ Q Factor Converter

Q Factor / Bandwidth Reference Table

Formulas

Related Topics

Bandwidth Theory

Find BW Tutorial

Q Factor Guide